I. Field of the Invention
This invention relates to a rotatable grip for actuating a derailleur type bicycle gear shifting system. More particularly, it relates to providing a gripping surface which is readily engaged by the thumb and index finger and possibly the middle finger, and the part of the palm between the thumb and index finger, while the remaining fingers of the hand encircle the normal hand grip on the handle bar, to move a cable which actuates the shifting mechanism.
II. Description of Related Art Including Information Disclosed Under 37 C.F.R. .sctn..sctn. 1.97 and 1.98
Derailleur type shifting mechanism for bicycles have in the past been actuated by levers supported on the handle bar or other fixed portions of the bicycle. The use of such levers normally requires the removal of a rider's hand from a hand grip in order to operate the lever to shift gears. This, of course, could contribute to the loss of steering control of the bicycle. However, shift actuators were later provided which are conveniently rotatably mounted on a handle bar and positioned so as not to require the rider to remove a hand from the hand grip to operate the shift actuator. One such shift actuator is disclosed in U.S. Pat. No. 4,900,291 issued Feb. 13, 1990 to one of the co-inventors of this application and assigned to the assignee of this application. Other patents assigned to the same assignee, which disclose rotatable shift actuators mounted on a handle bar inboard of the normal hand grip, are U.S. Pat. No. 4,938,733 issued Jul. 3, 1990, U.S. Pat. No. 5,102,372 issued Apr. 7, 1992, and U.S. Pat. No. 5,197,927 issued Mar. 30, 1993. The bicycle derailleur system in all of the above-mentioned patents is actuated by a rotatable grip which is located on the handle bar inboard of the normal hand grip. The gripping surface of rotatable grips currently sold by the assignee of this application, prior to this invention, were typically formed of foam rubber or neoprene which is secured to an underlying rotatable member of the actuating system. The outer surface of the foam rubber or neoprene rotatable grip was typically smooth, as shown in FIGS. 33 and 40 of U.S. Pat. No. 5,102,372 and FIGS. 21 and 40 of U.S. Pat. No. 5,197,927 referenced above.
While the above-referenced U.S. Pat. No. 4,900,291 in FIGS. 46 through 50, and U.S. Pat. No. 4,938,733 in FIGS. 46 through 58, and 67 reveal axially extending ribs formed on the outer gripping surface, such grips were found unsatisfactory by users and were discontinued. The grips with axially extending ribs as shown in these patents were formed of a hard plastic material such as ABS. The hard plastic grip with the axially extending grooves was in the past offered for sale as a commercial product, but was not well received. The ridges, being formed of hard plastic, presented harsh sharp edges to the operator's thumb and fingers. That is, when an operator would apply pressure to the edges of the ridges with a thumb and finger, or fingers, the edges would with repetitive shifting cause the thumb and finger or fingers to become sore and possible bruised or cut. The harsh sharp edges, taken in conjunction with normal bicycle motions, including bouncing of the bike, made it most uncomfortable to operate the grooved hard plastic rotatable grips. Thus, the hard plastic grip with ridges was quite quickly replaced with a smooth grip of a softer material as shown in the above-mentioned U.S. Pat. Nos. 5,102,372 and 5,197,927.